///
// * jdbm LICENSE v1.00
// *
// * Redistribution and use of this software and associated documentation
// * ("Software"), with or without modification, are permitted provided
// * that the following conditions are met:
// *
// * 1. Redistributions of source code must retain copyright
// *    statements and notices.  Redistributions must also contain a
// *    copy of this document.
// *
// * 2. Redistributions in binary form must reproduce the
// *    above copyright notice, this list of conditions and the
// *    following disclaimer in the documentation and/or other
// *    materials provided with the distribution.
// *
// * 3. The name "jdbm" must not be used to endorse or promote
// *    products derived from this Software without prior written
// *    permission of Cees de Groot.  For written permission,
// *    please contact cg@cdegroot.com.
// *
// * 4. Products derived from this Software may not be called "jdbm"
// *    nor may "jdbm" appear in their names without prior written
// *    permission of Cees de Groot.
// *
// * 5. Due credit should be given to the jdbm Project
// *    (http://jdbm.sourceforge.net/).
// *
// * THIS SOFTWARE IS PROVIDED BY THE ndbm PROJECT AND CONTRIBUTORS
// * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
// * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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// * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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// * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// * OF THE POSSIBILITY OF SUCH DAMAGE.
// *
// * Copyright 2000 (C) Cees de Groot. All Rights Reserved.
// * Contributions are Copyright (C) 2000 by their associated contributors.
// *
// * $Id: LogicalRowIdManager.java,v 1.3 2005/06/25 23:12:32 doomdark Exp $
// 


//*************************************************************************
//**  Included in JDMB 1.0 port to SharpDBM;  11/2013 Cyrus Neah cneah@codingreal.com
//**  SharpDBM is an independent reimplementation of the JDBM 1.0 software library in C#  
//*************************************************************************

using SharpDBM.helper;

namespace SharpDBM.recman
{


///
// *  This class manages the linked lists of logical rowid pages.
// 
	internal   class LogicalRowIdManager
	{
	// our record file and associated page manager
		private RecordFile file;
		private PageManager pageman;
		private FreeLogicalRowIdPageManager freeman;

//    *
//     *  Creates a log rowid manager using the indicated record file and
//     *  page manager
//     
 
//
		internal LogicalRowIdManager(RecordFile file, PageManager pageman)
		{
	  this.file = file;
	  this.pageman = pageman;
	  this.freeman = new FreeLogicalRowIdPageManager(file, pageman);

		}

//    *
//     *  Creates a new logical rowid pointing to the indicated physical
//     *  id
//     
 
//
		internal virtual Location insert(Location loc)
		{
  // check whether there's a free rowid to reuse
	  Location retval = freeman.get();
	  if (retval == null)
	  {
	  // no. This means that we bootstrap things by allocating
	  // a new translation page and freeing all the rowids on it.
		  long firstPage = pageman.allocate(Magic.TRANSLATION_PAGE);
		  short curOffset = TranslationPage.O_TRANS;
		  for (int i = 0; i < TranslationPage.ELEMS_PER_PAGE; i++)
		  {
		freeman.put(new Location(firstPage, curOffset));
		curOffset += PhysicalRowId.SIZE;
		  }
		  retval = freeman.get();
		  if (retval == null)
		  {
		throw new Error("couldn't obtain free translation");
		  }
	  }
  // write the translation.
	  update(retval, loc);
	  return retval;
		}

//    *
//     *  Releases the indicated logical rowid.
//     
 
//
		internal virtual void delete(Location rowid)
		{

	  freeman.put(rowid);
		}

//    *
//     *  Updates the mapping
//     *
//     *  @param rowid The logical rowid
//     *  @param loc The physical rowid
//     
 
//
		internal virtual void update(Location rowid, Location loc)
		{

			TranslationPage xlatPage = TranslationPage.getTranslationPageView(file.get(rowid.getBlock()));
			PhysicalRowId physid = xlatPage.get(rowid.getOffset());
			physid.setBlock(loc.getBlock());
			physid.setOffset(loc.getOffset());
			file.release(rowid.getBlock(), true);
		}

//    *
//     *  Returns a mapping
//     *
//     *  @param rowid The logical rowid
//     *  @return The physical rowid
//     
 
//
		internal virtual Location fetch(Location rowid)
		{

			TranslationPage xlatPage = TranslationPage.getTranslationPageView(file.get(rowid.getBlock()));
			try
			{
				Location retval = new Location(xlatPage.get(rowid.getOffset()));
				return retval;
			}
			finally
			{
				file.release(rowid.getBlock(), false);
			}
		}

	}

}